Further insight in the photochemistry of DNA: structure of a 2-imidazolone (5-4) pyrimidone adduct derived from the mutagenic pyrimidine (6-4) pyrimidone photolesion by UV irradiation

Ferrocenyl thiazolidine-2-thione ornamented 1D coordination polymers derived from coinage metal halides and pseudohalides

Three new ferrocene-functionalized thiazolidine-2-thione coinage metal coordination polymers with halides and pseudo-halides were synthesized and the nature of their weak interactions was assessed.

The Paternò–Büchi reaction – a comprehensive review

This review represents the most complete description of the scientific results obtained on a photochemical reaction described 110 years ago by an Italian scientist.

The variety of UV-induced pyrimidine dimeric photoproducts in DNA as shown by chromatographic quantification methods

Induction of DNA damage is one of the major consequences of exposure to solar UV radiation in living organisms. UV-induced DNA photoproducts are mostly pyrimidine dimers, including cyclobutane pyrimidine dimers, pyrimidine (6-4) pyrimidone photoproducts and Dewar valence isomers. In the last few decades, a large number of methods have been developed for the quantification of these pyrimidine dimers. The present review emphasizes the contribution of chromatographic techniques to our better understanding of the basic DNA photochemistry and the better description of damage in cells.

Oxetane synthesis through the Paternò-Büchi reaction

The Paternò-Büchi reaction is a photochemical reaction between a carbonyl compound and an alkene to give the corresponding oxetane. In this review the mechanism of the reaction is discussed. On this basis the described use in the reaction with electron rich alkenes (enolethers, enol esters, enol silyl ethers, enanines, heterocyclic compounds has been reported. The stereochemical behavior of the reaction is particularly stressed. We pointed out the reported applications of this reaction to the synthesis of naturally occuring compounds.

Simple ultraviolet and high-performance liquid chromatography methods for the evaluation of sunscreen efficacy

BACKGROUND

To prevent DNA damage caused by the ultraviolet (UV) radiation of sunlight, sunscreens are commonly used to protect human skin. Current analysis of sunscreens' effectiveness is done through complicated procedures, including human exposure.

OBJECTIVE

We sought to design a simple system using thymidine-thymidine (TT) dinucleotides to analyze the effectiveness of sunscreens.

METHODS

We can directly analyze sunscreen effectiveness and the formation of TT photolesions simply by using UV spectrophotometry and high-performance liquid chromatography (HPLC). Efficient sunscreen has protective effects against UV irradiation damage.

RESULTS

We have developed a simple method using TT dinucleotide, UV, and HPLC for the analysis of sunscreen effectiveness. Our research indicates that the analytical results from UV are consistent with those of HPLC, which is used to monitor the formation of the TT photolesions. Moreover, both UV and HPLC analyses indicate that TT dinucleotides are better protected against UV damage, using the sunscreens with higher UVB sun protection factor (SPF) value, and that sunscreens with higher SPF lead to reduced photolesion formation. Our UV and HPLC analyses confirm the SPF grading of commercial sunscreens.

LIMITATIONS

In this experiment, only sunscreens were tested. The experiment, therefore, does not apply to other commercial products, such as cosmetic materials that claim UV protection as a secondary benefit.

CONCLUSION

In conclusion, we have established a simple strategy to analyze the effectiveness of sunscreens and the quality of these potential cancer-preventive products.

Organometallic radical-initiated cleavage of the metal chelate and thiazole rings in a cyclopentadienylchromium complex

Extensive ring cleavage in the mercaptobenzothiazole chromium complex CpCr(CO)2(SCSN(C6H4)) (2), initiated by cyclopentadienyl chromium tricarbonyl, produced novel polynuclear complexes 3-5.